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MF68237 - OSP-DB-OTHER-WAIT PARALLEL JOBS GET STUCK IN TIMW IN MODULE

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PTF ( Program Temporary Fixes ) Cover letter


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Abstract

OSP-DB-OTHER-WAIT PARALLEL JOBS GET STUCK IN TIMW IN MODULE


Pre/Co-Requisite PTF / Fix List

REQ  LICENSED           PTF/FIX  LEVEL

TYPE PROGRAM  RELEASE   NUMBER   MIN/MAX  OPTION
---- -------- --------- -------  -------  ------
NONE



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-------
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APAR Error Description / Circumvention

-----------------------------------------------
When several parallel Jobs are opening (optimizing) the same SQL
statement,
many Jobs get stuck in TIMW condition using no CPU and with a
callstack showing SKREFCOUNT.
Even when ending all jobs in RUN, the TIMW jobs won't progress.
The TIMW Jobs, which do not progress their work at all, can be
ended IMMED.

CORRECTION FOR APAR MA48797 :
-----------------------------
The jobs were waiting to obtain a lock. In some cases if other
jobs waiting for the same lock were ended while waiting, the
remaining jobs waiting for the lock will never be unblocked. It
may be possible for this to also happen when a query completes
while an AQP thread is doing an EKR.

The SkRefCount used to provide the locking has been updated so
that waiters will not be indefinitely blocked when other waits
are canceled.

CIRCUMVENTION FOR APAR MA48797 :
--------------------------------
None.


Activation Instructions


None.




Special Instructions


None.


Default Instructions

THIS PTF CAN BE APPLIED IMMEDIATE OR DELAYED.



Supersedes

PTF/FIX NO(S).  APAR TITLE LINE
--------------  ------------------------------------------------------------
     NONE

Summary Information

System..............................i
Models..............................
Release.............................V7R3M0
Licensed Program...............5770999
APAR Fixed..........................View details for APAR MA48797
Superseded by:......................
Recompile...........................N
Library.............................QSYS
MRI Feature ........................NONE
Cum Level...........................C1098730


IBM i Support

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Document Information

Modified date:
17 April 2021